The plot line in Shakespeare's Hamlet concerning Ophelia helps the audience understand the nature of the court and its social politics and intrigues. It shows how under the monarchical system, where power is concentrated in a king, courtiers constantly spend time maneuvering for favor, often lying or using others as pawns in an effort to get ahead in an arena where the whim of the king is the root of all power.
Ophelia herself is a sweet innocent girl who does everything right by the standards of her period. She is chaste and loyal to her family and Hamlet, and she is eventually driven insane by psychological abuse. She is a tragic and sympathetic character whose innocence is exploited by the men around her and makes us aware of the damage patriarchy and the quest for power do to harm the innocent.
Polonius views Ophelia as a pawn whose marriage potential he can use to his own advantage. This shows him to be selfish and manipulative, treating his own daughter not as a beloved child but simply as a tool. Scenes with Ophelia reveal Polonius' duplicitous and selfish nature.
Laertes has some genuine concern for his sister, but despite that, she is aware of his hypocrisy and bad character. The contrast between brother and sister highlights the moral failings of the brother by contrast with the simple virtue of the sister. The love of Laertes for his sister shows him as fallible rather than evil and makes him a mixed character rather than pure villain.
Although Hamlet is the sympathetic protagonist of the play, his treatment of Ophelia makes him an imperfect hero. Although readers will sympathize with his love of his father, his vengefulness makes him drive to suicide an innocent young woman who genuinely loves him and reveals a dark and morally negative aspect to his character.